NASA yeast turns plastic waste into food
Researchers have engineered yeasts to convert plastic bottles and crop waste into edible proteins and nutrients, creating a 3D-printed cookie.
A research team at Southern Illinois University Carbondale has developed a method to turn plastic bottles and agricultural waste into edible food. The work, funded by NASA's Deep Space Food Challenge, was presented this week at the American Chemical Society's fall meeting in Chicago.
Associate professor Lahiru Jayakody explained the logic behind the project. "We were trying to develop technologies for plastic upcycling to make more valuable products. We thought, why not focus on making food?" he said. The team programmed yeasts to convert waste materials into proteins, vitamins, and flavor compounds, then 3D-printed the result into a protein-rich cookie called µBites, pronounced 'microbites.'
From Bottle to Biomass
The process focuses on polyethylene terephthalate (PET), the common plastic in soda and water bottles. The team combined PET with discarded corn stalks and leaves. They used a technique called oxidative hydrothermal dissolution, developed at SIU Carbondale by geology professor Ken Anderson. This method uses water and oxygen under high temperature and pressure to break tough materials into fragments microbes can eat.
Engineered yeasts, including baker's yeast, then consume those fragments. The yeasts reform the material into proteins, fats, and acids. Fiber, starch, and sweetener are added to the mixture before it is extruded through a 3D printer to form the cookie. Jayakody and graduate student Sandhya Jayasekara led the yeast engineering work.
This approach mirrors existing biomanufacturing. For example, insulin is now produced by programmed yeast instead of being extracted from animals. "Microbes are very clever. So, we are using their traits to solve the problems we created," Jayakody said.
Engineering Flavor and Nutrition
Initial data indicates µBites are safe to eat, though the team awaits institutional approval before conducting formal taste tests. In aroma testing, most participants said they would be willing to eat the cookies in resource-limited situations.
To make the product more appealing, Jayasekara engineered additional yeast strains. One strain enables baker's yeast to produce vanilla flavoring directly from plant biomass. A separate strain converts ethylene glycol from PET into beta-carotene, which the human body turns into vitamin A. "We're using microbes to develop the cookie into a more attractive, consumer-friendly product," Jayasekara stated.
The team's long-term goal is to produce every ingredient in µBites using microbes, including the added starch, fiber, and sweetener. Jayakody expects the cookies could become publicly available within a few years. Potential applications range from use in disaster zones and submarines to future lunar or Martian outposts.
The research cites United Nations projections that global food demand could rise between 35 and 56 percent by 2050. Roughly 30 percent of the world's population is projected to be at risk of hunger. "The way to address that, I believe, is by using microbes," Jayakody concluded.
